Tannenberg

Tannenberg - Credit: Wikimedia Commons

Führerhauptquartier Tannenberg (also known as "Installation T") was a Führer Headquarters built in 1939 for use as a military command and control facility by Adolf Hitler. It was located near Freudenstadt and Hitler stayed there for a week in 1940 while inspecting the fortresses that formed the Maginot Line. Read more on Wikipedia

type: military installation
date from: 1939

Source: en.wikipedia.org